Government forces appeared to have cut off exits from the areas around Kauda and Gidel, reports said.
A bombing attack on Tonj in Bahr el Ghazal region Thursday came as the government announced a halt to air raids on rebel positions, the Sudan Catholic Information Office said.
Among those who fled were priests and personnel working with Bishop Macram Max Gassis of El Obeid Diocese, reported a relief fund that bears his name.
The bishop, in Canada to raise the alarm about the human rights violations by the Khartoum regime during the long civil war, issued the following statement: “I invite all people of good will, whatever their religion, to pray for the people and my personnel in the Nuba Mountains. They are under a massive, ongoing bombardment and military attack. Many villages have been burned, many people have been killed, many have become refugees as a result of these attacks.”